Magnetron discharge tube oscillator and frequency multiplier



5, 1939. K. FRITZ 2,169,725

MAGNETRON DISCHARGE TUBE OSCILLATOR AND FREQUENCY MULTIPLIER Filed Nov. 16, 1937 MAG/V5776 FIELD 00/1 Ge nerafoi MAGNET/C FIELD COIL flfifenna 7 0 @nt? c onfraz Generator l-y l'l-r-l-l l-l-lx MAGNET/C ALE FIELD 00/4 I X9 4 5 lnfezw 6 R .yK v 2 \4/ A 4 b I 3 H M- 2 INVENTOR KARL FRITZ ATTORNEY Patented Aug. 15, 1939 MAGNETRON DISCHARGE TUBE OSCIL- LATOR AND FREQUENCY MULTIPLIER Karl Fritz, Berlin, Germany, assignor to Telefunken Gesellschaft fiir Drahtlose Telegraphic m. b. 11., Berlin, Germany, a corporation of Germany Application November 16, 1937, Serial No. 174,771 In Germany October 13, 1936 7 Claims. (Cl. 250-36) The present invention is concerned with circuit organizations adapted to master control or excitation of a magnetron tube, especially for the frequency multiplication of ultra-short waves.

Circuit organizations are known for the master oscillation of split-anode magnetron tubes which require the use of special electrodes which serve solely for control ormodulator action. It has also been suggested in the earlier art to operate a four-split anode typeof magnetron as a master-driven amplifier in such a Way that two opposite segments play the part of control electrodes, and the other pair the part of working electrodes.

In the present invention, contradistinct to earlier suggestions, circuit organizations are dealt with designed to insure master action without distinct control electrodes.

The circuit arrangement here disclosed for master control, especially frequency multiplication, comprising the use of split-anode magnetron tubes with a numbe'r of segments divisible by four has the outstanding feature that one and the same segments play at the same time thepart of control and working electrodes in such a manner that the segments designed to set up the control field are combined in a different manner than for the production of the useful field, in electrical regard.

As a general rule this is accomplished by so combining the segments that, as regards the control field, they function like a split-anode magnetron, and as regards the useful field, they operate like a four-split magnetron.

In carrying out my invention I provide a magnetron discharge tube of the type which includes preferably four anode segments surrounding a linear cathode. These segments are arranged in interconnected pairs and the conductors which form the interconnections and which possess nodal points are also interconnected at said nodal points by a resonant loop, .the distributed inductance and capacitance of which are such as to provide resonance at a frequency harmonically related to the frequency of each conductor extending between individual segments of a pair. The segments of a pair may in accordance with one embodiment be adjacent one another circumferentially. According to another embodiment of the invention diametrically opposed segments may constitute a pair.

Figs. 1 and 2 show the forms of circuit arrangements that are fundamentally feasible, while Fig. 3 shows an electrically complete circuitscheme. Numerical factors :1: added'to the electrical data are to indicate whole numbers of integers. In connection with M4 the numbers are throughout odd. Thus, for example, the

factors an, 3:2, m3, $4, $5 and :re represent any convenient odd integers which may be selected in accordance with a practical design of the circuit arrangement.

Fig. 1 shows the principle of an embodiment of,the circuit organization here concerned comprising the use of a four-split anode magnetron. The anode segments A1A4 are mounted symmetrically in reference to the cathode K. Pairs of adjacent segments are interconnected through a parallel-wire system a, and b, respectively. Both parallel-wire systems are so proportioned that they correspond to a double-wire line of M2 length so far as the control-wave length (control frequency) is concerned. It will be remembered that a double-wire line of a length of M2 represents a short-circuit for the reference wave. The segments A1 and A2, and A3 and A4, respectively, as will thus be noted, are practically shortoircuited so far as the control frequency is concerned just as if they were directly united through a non-inductive clip or loop.

Now, the situation is entirely different for the useful (signal) frequency. So far as this frequency is concerned, it is possible, for instance, by the aid of a tuning bridge piece B shiftable in th direction ofthe arrow, to find a setting which will correspond to M4 or a multiple of M4 as regards the useful wave length. What is insured by this latter step is that the adjacent or jutaposed segments are united just as by an oscillatory circuit tuned to the useful or signal frequency and are able toexcite the same. Connected with each of the electrical midpoints Ma and Mb of the parallel-wire systems a and b are the respective conductors of a third parallel-wire system c. In a circuit arrangement of the kind shown in Fig. 1, the said third system (2 serves to supply the control potential, and the same, including its extensions consisting of the parallel conductors of systems a and b is tuned to M4 or a multiple thereofin reference to the control wave length. The control generator, in a scheme as in Fig. 1, is in coupling relationship with system c, and the useful (load) circuit with the two systems a, b.

Fig. 2 shows the second fundamentally feasible form of construction of the basic idea of this invention. symmetrically mounted in reference to acathode K are four anode segments A1 to A4. In this instance, contradistinct from Fig. 1, two opposite segments are interconnected through a parallel-Wire system a and b, respectively. Both parallel-wire systems are so proportioned that they correspond to a double-wire line of a length of M2, so far as the useful wave length is concerned. The segments A1, A2, and A3, A3, respectively, so far as this last named wave length is concerned, may be regarded as being shortcircuited just the same as if they were connected through a non-inductive loop.

The conditions are totally different as regards control frequency, for so far as the latter isconcerned it is possible for instance, by the aid of tuning bridges B shiftable in the direction of the arrow to determine a setting which corresponds to M4 or a multiple thereof, so far as the control- Wave length is concerned. The result is the same as if the segments A1, A2, and A3, A4, respectively, were connected through an oscillatory circuit tuned to the control frequency. The introduction of the control energy, and the taking off of the useful energy, of course, must be effected in this circuit organization in a way different from. that in Fig. l. The control potential must be impressed upon the two systems a and b in such a way that the adjacent segments have control potentials that are in phase, in order that the tube, so far as the control field is concerned, may function like a two-split magnetron. The useful energy is put out at the third system c which, in-

cluding its extensions, is tuned to M4 or a multiple of the useful wave.

Fig. 3 shows a complete electrical circuit scheme which includes also the source of D. C., the con-- 7, trol potential source, and the consumer or load.

The magnetron tube which is comprised in this circuit organization is confined within a. gas-tight vessel G. For instance, the segments A1 and A: have fitted to the edges thereof radial extensions R which are designed to suppress any tendency towards self-oscillation of the segments A1, A2, and A3, A4, operating in synchronism in reference to the control frequency. The radial (baffle) sheets or extensions are intended to prevent segments Working in parallel as regards the control frequency from directing electrons towards each other.

But as to the rest, this circuit organization corresponds to the fundamental embodiments shown in Fig. l. The parallel-wire systems a and b are so proportioned that they result in a circuit tuned to M2 or a multiple thereof, so far as the control-wave length is concerned. The same parallel-wire systems, with due regard for the mutual capacitance of the segments (intersegment ca.- pacitance) are moreover tuned by the aid of shiftable tuning bridges B to M4 or a multiple thereof, as regards the useful Wave-length. The output circuit N, which is brought to a consumer or load, say, antenna V is coupled with both parallel-wire systems a. and b in such a Way that in the circuit N the oscillations of both systems multiplied in their frequencies will become added. Connected with each of the electrical mid-points Ma and Mb of the two systems a and b is the respective conductor of the third parallel-wire system C. This last named system together with its extensions which consist of the parallel-connected conductors of the systems a and b, respectively, is tuned to M4 or a multiple thereof, as regards the control wave-length, and coupled with a separate oscillation circuit St which is excited from a master oscillator or transmitter O. The supply of the positive biasing potential to the anode segments is effected suitably at the electrical midpoint M0 (point of symmetry) of the third system. As far as possible intercoupling of the two loops A and B may be avoided by mounting these loops at an angle to one another. Furthermore, the loop C may be advantageously disposed in a plane which intersects the planes occupied by each of the loops A and B. In this manner objectionable intercoupling between the input and output circuits is avoided.

As regards Fig. 3, the following example is given:

A control frequency is assumed which has a wave length \=100 cm. The derived frequency is assumed to have a wave length )\n=50 cm. The resonant characteristics of the various loops A, B and C are preferably obtained by fixing their effective electrical lengths sothat their ratios are in accordance with odd integral numbers. More specifically, it is preferable that these ratios should be as follows:

ms=1; m9=3 and 5; and r7=3 So far as M2 is concerned, the inter-electrode capacitance is negligible because the electrodes are excited in phase for the place in question. But for tuning to M4 the mutual capacitances are appreciable, with the result that the oscillatory circuit becomes smaller in geometric respect.

The idea underlying the present invention is not restricted to the exemplified embodiments hereinbefore described and illustrated in the drawing. The useful circuit and the control circuit, if desired, could be coupled also conductively.

I claim:

1. A master-oscillation circuit system adapted for frequency multiplication comprising a splitanode magnetron discharge tube having a number of anode segments divisible by four, means including circuits having resonance at a control frequency interconnecting certain of said segments for causing the same to be operated as control electrodes, and means including a circuit having a resonance frequency harmonically related to that of the aforementioned circuits, and being connected to nodal points on the same for causing all of said segments to be operable as output electrodes.

2. A high frequency oscillation generator and frequency multiplier comprising a magnetron discharge tube having a plurality of pairs of anode segments, a plurality of resonant parallel-wire systems directly connected across different pairs of anode segments and another parallel-wire system constituting an oscillatory circuit tuned to one-quarter of the wave length of the fundamental frequency generator, the last said system being connected across nodal points of two of the first said parallel wire systems.

3. An oscillation generator comprising a magnetron discharge tube having a cathode and a plurality of surrounding segmented anodes, and having radial baflle plates attached to and extending inwardly from certain edges of said segmented anodes.

4. An oscillation generator comprising an electron discharge device including a centrally disposed linear cathode and two pairs of anode segments surrounding said cathode, a magnetic field producer effective upon the discharge space within the anode segments, two conductors each interconnecting the two segments of an appropriate pair, said conductors being tuned by their distributed inductance and capacitance to a given frequency, a resonant loop interconnecting nodal points on each of said two conductors, said loop providing resonance at a frequency harmonically related to said given frequency, means for impressing frequency control impulses upon certain of said anode segments, and means for delivering output energy at said harmonically related frequency from all of said anode segments.

5. An oscillation generator in accordance with claim 4 and having said two conductors which interconnect individual segments tuned to the frequency of said control impulses.

6. An oscillation generator in accordance with claim 4 and having said resonant loop coupled to said means for impressing frequency control impulses upon certain of said anode segments.

7. An oscillation generator in accordance with claim 4 and having one segment in each pair arranged with an edge folded inwardly, thereby to intersect the spiral paths of certain electrons as produced under the influence of said magnetic field.

KARL FRITZ. 

